debit order problems

I have been charged R150 for an unpaid Magtape when I have repeated came to nedbank first Clearwater mall then Randridge mall and requested for NEDBANK to stop that debit order from going out now I have been out of the country for almost 3 months it come on going out then returning as unpaid and am getting charged. The last time I approached the bank I was told that you as nedbank would be implementing a SMS option that will allow me to accept or decline a debit order from occurring in my account. Now my account is in arrears you keep sending me SMS's to rectify it yet you are penalizing me for a debit order you are failing to stop after countless times of requesting you to stop the debit order , I have even stopped keeping money in my account cause I don't want to be paying for that debit order. I really need this to be fixed cause I can not pay a penalty for something I have physically stood in a queue for repeatedly and requested for you to stop that debit order . I refuse to pay for such a penalty. or are telling me that you as my bank are unable to stop a debit order from going out of my account?????????????